This invention pertains to a type of link plate for a silent chain and having a pair of teeth, a type of silent chain containing the link plates, and a method for assembling the silent chain.
As shown in the side view of FIG. 9, a silent chain usually has plural link plates 20 stacked in the thickness direction and in the longitudinal direction. They are connected by connecting pins 30 in pivoting manner, and guide links 40 are arranged on the outside of the outermost link plates 20.
As shown in the enlarged view of FIG. 8, each of link plates 20 that form silent chain 1 has a pair of pin holes 21 for inserting the connecting pins, and a pair of teeth 22 extending downward. Tooth 22 is composed of nearly arcuate inside flank surface 22a, nearly straight outside flank surface 22b, and tooth tip part 22c that connects them, and adjacent inside flank surfaces 22a are connected by crotch 23. Also, link plate 20 has nearly straight back side part 24, and back side part 24 and outside flank surface 22b are connected to each other by nearly arcuate shoulder part 25.
In silent chains developed recently, link plates with different plate thicknesses are used in the same silent chain. Also, there is demand for the use of link plates having different materials, heat treatments, or hardnesses within the same silent chain.
In this case, when the link plates having different plate thicknesses, materials, heat treatments, or hardnesses are assembled, it is necessary to differentiate the various types of link plates from each other in order to set them at their respective appropriate positions. However, all of the link plates have the same outer shape in the conventional silent chain, so that in the assembly operation it is hard to differentiate the link plates having different materials, heat treatments, or hardnesses from each other by their appearances. Also, for link plates having different plate thicknesses, because the difference in plate thickness is only a fraction of a millimeter, it is not easy to identify link plates having different plate thicknesses.
The invention provides a solution to the aforementioned problems of the conventional methods by providing a type of link plate that can be identified by its appearance, a type of silent chain having different types of link plates mixed together, and a method for assembling such a silent chain. The invention also provides a checking method to determine whether two types of link plates in the silent chain are placed at their respective designated positions.
According to a first aspect of the invention a type of link plate for a silent chain may be provided having a pair of teeth, each of which is composed of an inside flank surface, an outside flank surface and a tooth tip part that connects them. The tooth tip part can have a shape formed by cutting off a portion on the side toward the outside flank surface.
According to a second aspect of the invention a type of link plate for a silent chain may be provided having a pair of teeth, each of which is composed of an inside flank surface and an outer side surface. The outside flank surface and the back side part can be connected by a shoulder part having a bump portion that projects outward.
According to a third aspect of the a type of link plate for a silent chain may be provided having a pair of teeth, each of which is composed of an inside flank surface and an outside flank surface and a tooth tip part that connects them. The outside flank surface and the back side part can be connected by a shoulder part. The tooth tip part may have a shape formed by cutting off a portion on the side toward the outside flank surface and the shoulder part may have a bump portion that projects outward.
Thus, the link plate pertaining to the first aspect of the invention may be formed with a portion of the tooth tip part cut off on the side toward the outside flank surface. In the second aspect of the invention, a bump portion projecting outward may be formed on the shoulder part of the link plate. In the third aspect of the invention, the link plate may be formed with a portion of the tooth tip part of the link plate cut off on the side toward the outside flank surface, and with a bump portion projecting outward formed on the shoulder part of the link plate. In this way, according to the aspects of the invention, the link plates can be differentiated easily from each other and from conventional link plates.
Also, the portion pertaining to the difference in appearance of the link plate is preferably not the portion pertaining to engagement with the sprocket, and it is preferably irrelevant to the strength of the link plate. From this viewpoint, the portion of the tooth tip part on the side toward the outside flank surface and the shoulder part may be selected for this purpose.
According to another aspect of the invention a type of silent chain may be provided having a plurality of link plates, each of which may have a pair of pin holes for inserting connecting pins and a pair of teeth each composed of an inside flank surface, an outside flank surface and a tooth tip part that connects them. The plural link plates can be connected to each other by the connecting pins in a pivotable manner. The link plates may include both a first type of link plates, which may have the tooth tip part shaped by cutting off a portion on the side toward the outside flank surface, and a second type of link plates, which may have the tooth tip part not shaped by cutting off a portion on the side toward the outside flank surface, and the two types of link plates may be mixed together.
According to another aspect of the invention a type of silent chain may be provided having a plurality of link plates, each of which has a pair of pin holes for inserting connecting pins and a pair of teeth each composed of an inside flank surface and an outside flank surface, with the outside flank surface and the back side part connected to each other with a shoulder part. The plurality of link plates may be connected to each other by the connecting pins in a pivotable manner. The link plates may include a first type of link plates each having a bump portion projecting outward from the shoulder part, and a second type of link plates without a bump portion projecting outward from the shoulder part, and the two types of link plates may be mixed together.
According to yet another aspect of the invention a type of silent chain may be provided having a plurality of link plates, each of which has a pair of pin holes for inserting connecting pins and a pair of teeth each composed of an inside flank surface, an outside flank surface and a tooth tip part that connects them, with the outside flank surface and the back side part connected to each other by a shoulder part. The plurality of link plates can be connected to each other by the connecting pins in a pivotable manner. The link plates may include a first type of link plates, which have the tooth tip part shaped by cutting off a portion on the side toward the outside flank surface and which have a bump portion projecting outward from the shoulder part, and a second type of link plates, which have the tooth tip part not shaped by cutting off a portion on the side toward the outside flank surface and which have no bump portion projecting outward from the shoulder part, and the two types of link plates may be mixed together.
For the silent chain pertaining to one of the above-described aspects of the invention, a first type of link plate having a shape with a portion of the tooth tip part cut off on the side toward the outside flank surface and a second type of link plate having no such portion of the tooth tip part cut off on the side toward the outside flank surface may be mixed together. For the silent chain pertaining to another above-described aspect of the invention, a first type of link plate having a bump portion projecting outward from the shoulder part and a second type of link plate having no such bump portion projecting outward from the shoulder part may be mixed together. For the silent chain pertaining to yet another of the above-described aspects of the invention, a first type of link plate having a shape with a portion of the tooth tip part cut off on the side toward the outside flank surface and having a bump portion projecting outward from the shoulder part and a second type of link plate having no such portion of the tooth tip part cut off on the side toward the outside flank surface and having no such bump portion projecting outward from the shoulder part may be mixed together.
For the above described aspects of the invention, the first and second link plates described in them can be differentiated from each other by appearance. Consequently, it is possible to mix the first and second link plates together in the same silent chain.
According to an aspect of the invention, the silent chain described in the above aspects of the invention may be provided having the first and second link plates different from each other with respect to one or more of the following properties: plate thickness, material, heat treatment, hardness, and finish processing of the pin holes. Because the difference in plate thickness, material, heat treatment, hardness or pin hole finish processing is not clearly manifested in the appearance, the difference may be made clearly identifiable by means of the shape of the tooth tip part or shoulder of the link plate. Here, the difference in pin hole finish processing refers to difference between the case of finish processing by shaving processing etc. of the pin hole and the case of no finish processing.
According to another aspect of the invention, a method for assembling a silent chain according to an above-described aspect of the invention may be provided including detecting with a sensor or identifying with an identification gate whether the tooth tip part of the link plate has a shape with a portion cut off on the side toward the outside flank surface. When the link plate is detected by the sensor or identification gate to have a shape with a portion of the tooth tip part cut off, it can be set at the configuration position for the first type of link plate. When the link plate is detected by the sensor or identification gate to not have a shape with a portion of the tooth tip part cut off, it is set at the configuration position for the second type of link plate, and the first and second link plates may be connected to each other by connecting pins in a pivotable manner.
According to yet another aspect of the invention, a method may be provided for assembling a silent chain according to an above-described aspect of the invention including detecting with a sensor or identifying with an identification gate whether the shoulder part of the link plate projects outward. When the link plate is detected by the sensor or identification gate to have a shoulder part that projects outward, it can be set at the configuration position for the first type of link plate. When the link plate is detected by the sensor or identification gate to not have a shoulder part that projects outward, it can be set at the configuration position for the second type of link plate and the first and second link plates can be connected to each other by connecting pins in a pivotable manner.
According to another aspect of the invention, a method for assembling the silent chain according to an above-described aspect of the invention may include detecting with a first sensor or identifying with a first identification gate whether the tooth tip part of the link plate has a shape with a portion cut off on the side toward the outside flank surface, and detecting with a second sensor or identifying with a second identification gate whether the shoulder part of the link plate projects outward. When the link plate is detected by the first and second sensors or the first and second identification gates to have a shape with a portion of the tooth tip part cut off and to have a shoulder part projecting outward, it may be set at the configuration position for the first type of link plate. When the link plate is detected by the first and second sensors or the first and second identification gates to not have a shape with a portion of the tooth tip part cut off and to not have a shoulder part that projects outward, it may be set at the configuration position for the second type of link plate and the first and second link plates can be connected to each other by connecting pins in a pivotable manner.
For the method of assembly of the silent chain in accordance with an aspect of the invention, whether the link plate has a shape with a portion of the tooth tip part cut off on the side toward the outside flank surface may be detected with a sensor or may be identified with an identification gate. Also, according to another aspect of the invention, whether the shoulder part of the link plate projects outward may be detected with a sensor or may be identified with an identification gate. In addition, according to yet another aspect of the invention, whether the link plate has a shape with a portion of the tooth tip part cut off on the side toward the outside flank surface may be detected with a first sensor or may be identified with a first identification gate, and whether the shoulder part of the link plate projects outward may be detected with a second sensor or may be identified with a second identification gate.
Here, the identification gate refers to a gauge that has a hole shaped to match the contour of the link plate. For example, when this hole corresponds to the contour of the link plate having a shape with a portion of the tooth tip part cut off, the link plate with a portion of the tooth tip part cut off can pass through the identification gate, while the link plate without a portion of the tooth tip part cut off cannot pass through it. In this way, the identification gate can identify the two types of link plates.
According to further aspects of the invention, the first and second types of link plates according to above aspects of the invention can have their difference in appearance identified with a sensor or an identification gate. Consequently, when the first and second types of link plates are mixed together in the sample silent chain, it can be possible to place the various link plates in their respective designated configuration positions for assembly.
According to an aspect of a method for assembling the silent chain, an operational check step may be included in which, after assembly of the silent chain, whether the first and second link plates are respectively set at their designated positions may be checked by a sensor differentiated on the basis of the shape of the tooth tip part.
According to an aspect of a method for assembling the silent chain, an operational check step may be included in which after assembly of the silent chain, whether the first and second link plates are respectively set at their designated positions may be checked by a sensor differentiated on the basis of the shape of the shoulder part.
According to an aspect of a method for assembling the silent chain, an operational check step may be included in which, after assembly of the silent chain, whether the first and second link plates are respectively set at their designated positions may be checked by a sensor differentiated on the basis of the shapes of the tooth tip part and the shoulder part.
According to an aspect of the method for assembling the silent chain, after assembly of the silent chain, whether the first and second types of link plates are set at their respective designated positions may be checked by a sensor differentiated on the basis of the shape of the tooth tip part. Also, according to another aspect of the invention, after assembly of the silent chain, whether the first and second types of link plates are set at their respective designated positions may be checked by a sensor differentiated on the basis of the shape of the shoulder part. In addition, in yet another aspect of the invention, after assembly of the silent chain, whether the first and second types of link plates are set at their respective designated positions may be checked by a sensor differentiated on the basis of the shape of the tooth tip part and the shape of the shoulder part.
According to aspects of the invention described above, whether the first and second types of link plates are set at their respective designated positions may be checked by a sensor. Consequently, it may be possible to prevent shipment of mis-assembled silent chains.